Rajeev Pillay

Alumnus, Western Ghats

MSc (Zoology), University of Calcutta, India (2004)

I joined NCF in November 2007. My research is centered on understanding spatiotemporal patterns in large mammal distributions in the Western Ghats and the processes underlying observed changes in these patterns. The work so far has revealed important patterns in the distribution and abundance of large mammals over time. Yet, there remains much to understand about the processes that are driving the patterns. My present focus is on modeling large mammal occupancy dynamics over space and time as a function of landscape and environmental predictors, anthropogenic threats and, life-history traits.

I am currently a Ph.D. Candidate in Wildlife Ecology and Conservation at the University of Florida, Gainesville. For my doctoral dissertation, I am investigating the impact of logging and rainforest fragmentation on animal behavior and species interactions. Specifically, I am testing hypotheses pertaining to: (i) the responses of breeding songbirds to perceived predation risk, (ii) frugivore-fruit mutualistic interactions and, (iii) post-dispersal seed predation. I work in Sabah, Malaysian Borneo at the field sites of the Stability of Altered Forest Ecosystems (S.A.F.E.) Project.

Previously, I was a researcher with the All India Tiger Monitoring Project at the Wildlife Institute of India, Dehradun (2004-05) and worked in Kanha, Pench and Satpura Tiger Reserves in Madhya Pradesh. Thereafter, during 2006-07, I worked with the Wild Rescue Program at the Wildlife Trust of India in New Delhi.

Karnataka state in southern India supports a globally significant—and the country’s largest—population of
the Asian elephant Elephas maximus. A reliable map of Asian elephant distribution and measures of spatial
variation in their abundance, both vital needs for conservation and management action, are unavailable
not only in Karnataka, but across its global range. Here, we use various data gathered between 2000 and
2015 to map the distribution of elephants in Karnataka at the scale of the smallest forest management
unit, the ‘beat’, while also presenting data on elephant dung density for a subset of ‘elephant beats.’
Elephants occurred in 972 out of 2855 forest beats of Karnataka. Sixty percent of these 972 beats—and
55% of the forest habitat—lay outside notified protected areas (PAs), and included lands designated for
agricultural production and human dwelling. While median elephant dung density inside protected areas
was nearly thrice as much as outside, elephants routinely occurred in or used habitats outside PAs where
human density, land fraction under cultivation, and the interface between human-dominated areas and
forests were greater. Based on our data, it is clear that India’s framework for elephant conservation—
which legally protects the species wherever it occurs, but protects only some of its habitats—while being
appropriate in furthering their conservation within PAs, seriously falters in situations where elephants
reside in and/or seasonally use areas outside PAs. Attempts to further elephant conservation in production and dwelling areas have extracted high costs in human, elephant, material and monetary terms in
Karnataka. In such settings, conservation planning exercises are necessary to determine where the needs
of elephants—or humans—must take priority over the other, and to achieve that in a manner that is based
not only on reliable scientific data but also on a process of public reasoning.

Much research in conservation biogeography is fundamentally dependent on obtaining reliable data on species distributions across space and time. Such data are now increasingly being generated using various types of public surveys. These data are often integrated with occupancy models to evaluate distributional patterns, range dynamics and conservation status of multiple species at broad spatio-temporal scales. Occupancy models have traditionally corrected for imperfect detection due to false negatives while implicitly assuming that false positives do not occur. However, public survey data are also prone to false-positive errors, which when unaccounted for can cause bias in occupancy estimates. We test whether false positives in a dataset collected from public surveys lead to overestimation of species site occupancy and whether estimators that simultaneously account for false-positive and false-negative errors improve occupancy estimates.

Location

Western Ghats, India.

Methods

We fit occupancy models that simultaneously account for false positives and negatives to data collected from a large-scale key informant interview survey for 30 species of large vertebrates. We tested their performance against standard occupancy models that account only for false negatives.

Integrating large-scale public surveys with occupancy modelling approaches is a powerful tool for informing conservation and management. However, in many if not most cases, it will be important to explicitly account for false positives to ensure the reliability of occupancy estimates obtained from public survey datasets such as key informant interviews, volunteer surveys, citizen science programmes, historical archives and acoustic surveys.

Journal Article

2011

Patterns of spatiotemporal change in large mammal distribution and abundance in the southern Western Ghats, India

Large mammals face high risks of anthropogenic extinction owing to their larger body mass and associated life history traits. Recent worldwide mammal declines have highlighted the conservation importance of effective assessments of trends in distribution and abundance of species. Yet reliable data depicting the nature and extent of changes in population parameters is sparse, primarily due to logistical problems in covering large areas and difficulties in obtaining reliable information at large spatial scales, particularly over time. We used key informant surveys to generate detection histories for 18 species of large mammals (body mass > 2 kg) at two points in time (present and 30 years ago) in the Southern subregion of the Western Ghats global biodiversity hotspot. Multiple-season occupancy models were used to assess temporal trends in occupancy, detectability and vital rates of extinction and colonization for each species. Our results show significant declines in distribution for large carnivores, the Asian elephant and endemic ungulates and primates. There is a significant decline in detectability for 16 species, which suggests a decline in their abundance. These patterns of change in distribution and abundance repeat in our assessments of spatial variation in occupancy dynamics between the three contiguous forest complexes and two human-dominated landscapes into which the southern Western Ghats has been fragmented. Extinction rates are highest in the human-dominated landscapes. Declines in abundance for several species suggest the presence of extinction debts, which may soon be repaid with imminent range contractions and subsequent species extinctions unless immediate remedial conservation measures are taken. Detection/non-detection surveys of key informants used in an occupancy modeling framework provide potential for rapid conservation status assessments of multiple species across large spatial scales over time.

The clear night sky had caused the temperature to plummet and a myriad stars cast a dim glow as Joseph and I drew up on our bike at the junction of a sal Shorea robusta forest patch and a meadow. As Joseph switched off the engine, the headlight went out and we were plunged into darkness. I dismounted, switched on the radio-receiver and raised the H-antenna above my head,making sweeping arcs to catch a signal from the radio-collar of the tigress we were tracking. The radio crackled to life and I immediately heard the clicks, loud and clear, indicating that the tigress was near at hand. Hardly had I done so, when a deafening roar erupted from the bushes.

Journal Article

2010

Ensuring the future of the tiger and other large mammals in the southern portion of the Nilgiri Biosphere Reserve, southern India

The Nilgiri Biosphere Reserve, at the tri-junction of Tamil Nadu, Kerala and Karnataka, constitutes arguably one of the finest conservation landscapes in the global range of the tiger. We surveyed the southern part of this region, as well as the adjoining areas, to assess the status of large mammals both within and outside protected areas. Our field assessments suggest that large mammals are almost exclusively confined to protected areas with the few remaining populations outside under severe threat from habitat degradation and poaching. However, large stretches of contiguous forests still remain. We suggest the extension of the recently notified Mudumalai Tiger Reserve in Tamil Nadu such that connectivity is retained and strengthened with Biligiri Rangaswamy Temple Wildlife Sanctuary of Karnataka to the north-east and with Silent Valley National Park of Kerala to the south. We also provide suggestions on strengthening conservation in this landscape. The involvement of local communities in the establishment of the Siruvani Conservation Reserve in Kerala and Tamil Nadu, and Nilambur Conservation Reserve in Kerala, will bolster the conservation of large mammals in this landscape. With the suggested extension, Mudumalai Tiger Reserve has the potential of becoming arguably the finest habitat for tigers across Asia, given the variations in altitude, topography and climate which produce a diversity of vegetation types and consequently, provide the tiger with an assortment of prey ranging from Nilgiri Tahr in the high altitude montane grasslands to Blackbuck in the low-lying dry deciduous and thorn scrub forests.

Despite a diverse assemblage of small carnivores in the forests of the southern Western Ghats in India, there is a paucity of information on their ecology, distribution, behaviour and current conservation status. Chance observations generated during surveys for other purposes are therefore useful. Sightings and signs of small carnivores were recorded opportunistically during a study to assess the distributions of larger mammals in the southern Western Ghats. The study yielded sightings of seven species of viverrids, herpestids and mustelids. The Common Palm Civet Paradoxurus hermaphroditus and Small Indian Civet Viverricula indica were sighted most frequently. The restricted-range Brown Palm Civet Paradoxurus jerdoni was sighted once.

Popular Article

2009

Mountain rainforests. Quest for large mammals in the southern Western Ghats

The jeeps forming a crescent beside the forest stream switched on their headlights almost simultaneously, brightly illuminatingthe drama unfolding before my eyes. Fifteen wild elephants were approaching the water from the forest beyond, unfazed by the presence of a horde of humans less than 20 m away. I was in Anakulam, a remote village in the rainforests near Eravikulam National Park in Kerala. During a field survey in the southernWestern Ghats, reports had filtered through of a fabled spot where elephants have been congregating since living memory to drink at a natural mineral spring. To ascertain the veracity of these stories, the Nature Conservation Foundation (NCF) team, led by Dr. A.J.T. Johnsingh, braved the rough, mountainous roads to Anakulam (meaning ‘elephant pond’) through dense Ochlandra reed brakes, arriving at dusk, only to find the locals playing cricket beside the stream!

Conference Proceedings

2009

Opportunities and challenges for tiger (Panthera tigris) conservation in the southern Western Ghats, India

The southern Western Ghats is an important ecological subunit of the Western Ghats biodiversity hotspot. Dominated by moist forests, including tropical wet evergreen forests, it has higher levels of biodiversity and endemism than the rest of the Western Ghats. There are 19 Protected Areas in the southern Western Ghats that cover 36% of its total area, among which Parambikulam, Anamalai and Periyar Tiger Reserves stand out as primary source habitats for tigers. The region is fragmented from north to south into the Anamalai, Periyar and Agasthyamalai landscapes. Given the crucial need for large, contiguous areas to ensure the persistence of wide-ranging large predators such as the tiger Panthera tigris and its prey, it is important to establish and maintain habitat connectivity within and between these landscapes, whereas conservation efforts today are focused on small, insular protected areas. Possibilities for forging connectivity between the Anamalai and Periyar landscapes along Kerala state are nonexistent owing to the loss of Devikulam Range in Munnar Forest Division to cardamom cultivation and developments related to tourism and Kumily Range in Kottayam Forest Division to encroachment. The link on the Tamil Nadu side, along the steep eastern slopes of Theni Forest Division, is extremely narrow and consequently unsuitable for large mammal movement at present. Our surveys, however, point to the possibility of bridging this gap through a corridor at Kottavasal. Recent camera-trapping studies by the Wildlife Institute of India, Dehradun have highlighted the precarious situation of tigers in Kalakad-Mundanthurai Tiger Reserve in the Agasthyamalai landscape. Therefore, establishment of the Kottavasal corridor and the Kulathupuzha Conservation Reserve is a must to secure the future of tiger in the Agasthyamalai landscape. It is important that all endeavours now be made to enable the Anamalai and Periyar-Agasthyamalai landscapes to each sustain a minimum population of 100 adult tigers. Controlling poaching of prey species especially sambar Cervus unicolor, establishment of protected areas such as Kodaikanal, Megamalai and Kulathupuzha, acquisition of failed private estates to facilitate large mammal recolonization and restoration of native vegetation in exotic species plantations are priority tasks that need immediate attention in order to realize the huge opportunities for tiger conservation in the southern Western Ghats.

A solitary rusty-spotted cat Prionailurus rubiginosus was sighted in a dry deciduous habitat of the Varushanad valley (9°40’ 3.72”N/77° 25’ 44.15”E) in Tamil Nadu, India on 6 June 2008. The Varushanad valley is located in the southern Western Ghats, an ecological subunit of the Western Ghats biodiversity hotspot.

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